1. Field of the Invention
This invention relates to a photographic camera having a built-in generator, and more particularly to a photographic camera provided with an electric shutter which is controlled by an electric control circuit supplied with electric power from an electric generator provided in the camera.
2. Description of the Prior Art
It has been known in the art to provide an electric generator in a camera for creating electricity upon release of a shutter release mechanism for supplying electric power to an electric shutter control circuit. In this kind of camera, an acting member engaged with the generator is moved overcoming the force of a strong spring upon film wind-up operaiton and the acting member is released to rotate the generator by the force of the spring to create electricity upon release of the shutter.
This kind of camera having a built-in generator suffers from a defect in that the electric power generated from the generator is not stable but is in proportion to the revolution speed of the generator. Therefore, when the generator starts to be driven, the electric power output has a rising characteristic. Accordingly, there is a fear that the shutter control circuit be supplied with unstable current and incorrectly operate. Further, when it is desired to open a shutter for a long time, the generator must keep on rotating for a long time until the shutter it to be closed. This requires a special means for keeping the generator rotated and preventing the shutter control circuit from being supplied with the rising power output.
Further, if this kind of camera having a built-in generator is provided with a slow shutter speed warning means which works to lock a shutter mechanism when the controlled shutter speed is too slow to obtain a sharp photograph, it sometimes happens that the generator is discharged without releasing a shutter to prevent the too slow speed shutter release. In such a case, it is required that the generator should be charged without winding up the film.